Conventionally, in a pressure sensor as shown in JP-A-2001-343298, bonding wires are covered with rubber or gel thereby protected from environmental conditions such as fluidity and corrosion of pressure medium as a measuring object, and reliability is ensured.
Further, in a pressure sensor as shown in JP-3073442 corresponding to U.S. Pat. No. 5,591,679, in a silicon chip, an area in which a gauge resistor (piezo element) is formed is covered with glass.
In recent years, in accordance with advancement of high-precision and multifunction vehicle control, there is a necessity to measure the pressure of a pressure medium with extremely high corrosiveness. However, in the pressure sensor disclosed in JP-A-2001-343298, as the bonding wires and peripheral connection structure are merely covered with rubber or gel, such pressure measurement on high corrosiveness pressure medium might degrade the rubber or gel and disable protection of the bonding wires and peripheral connection structure. Further, in the pressure sensor disclosed in JP-3073442, as the gauge resistor is merely covered with glass and the wirings are exposed, corrosion caused by the pressure medium cannot be prevented.